The detection and analysis of individual particles or cells in a suspension is important in medical and biological research. It is particularly important to be able to measure characteristics of particles such as concentration, number, viability identification and size. Individual particles or cells include, for example, bacteria, viruses, DNA fragments, cells, molecules and constituents of whole blood.
Typically, such characteristics of particles are measured using flow cytometers. In flow cytometers, particles which are either intrinsically fluorescent or are tagged and labeled with a fluorescent marker are caused to flow past a beam of radiant energy which excites the particles or labels or cells to cause emission of fluorescent light.
Conventional flow cytometry utilizes a flow cell that must be connected to a pressurized sample in order to force the sample into a flow cell cavity or lumen. The sample is then conducted by this pressure through the cavity or lumen, and then out the other end of the capillary into a sheath flow stream of buffer that is itself pressurized. This design requires complex flow cells that are expensive and require experts to install.